藻源性湖泛水体显黑颗粒的元素形态分析与鉴定

LakeSci．(湖泊科学)，2015，27(4)：591—598D0I10．18307／2015．0405@2015byJournalofkSciences藻源性湖泛水体显黑颗粒的元素形态分析与鉴定中秋实，范成新(中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室，南京210008)摘要：湖泛现象是我国超富营养化浅水湖泊面临的最严峻环境问题之一，水体发黑、发臭是湖泛水体最显著和基本的物理特征．针对太湖湖泛显黑颗粒缺乏从元素形态直接给出证据的问题，针对室内模拟藻体和沉积物存在下形成的湖泛水体，采用多种图谱分析技术，对厌氧截留分离的显黑颗粒物质及其化学组成和元素形态进行了分析鉴定．扫描电镜·x射线能谱分析与荧光光谱分析表明：湖泛水体显黑颗粒物质以藻类残体和悬浮沉积物颗粒物为主，其组成元素以C、0、Si为主；与未发生湖泛的对照样相比，湖泛水体显黑颗粒物样品中具有更高的Fe、s含量．X射线光电子能谱Fe、s微区分析进一步表明：湖泛显黑颗粒物样品中Fe主要以Fe(Ⅱ)的形式存在、S则以还原态s一的形式赋存，两者具有共同化合成FeS的充要条件．因此，缺氧厌氧条件下，湖泛水体的显黑物质组成是FeS，它可由水体中Fe和暑s通过化学共沉淀形成，并主要通过吸附于悬浮颗粒物之上而使得整个水柱呈现黑色，指示湖泛的暴发过程和维持状态．关键词：湖泛；显黑颗粒物；硫化物Identificationofblacksuspendedparticlesinthealgae—inducedblackbloomwatercolumnSHENQiushi&FANChengxin(StateKeyLaboratoryof妇ScienceandEnvironment，NanjingInstituteofGeographyandLimnology，ChineseAcademyofSciences，Nanjing210008，P．R．China)Abstract：Theblackbloomphenomenonisoneofthemostseriousproblemsinsomehyper—eutrophicshallowlakesinChina．TheblackCOIouYandoffensiveodourweretheirmostsignificantandbasicphysicalcharacteristics．However，nofirmingevidenceshadbeenpresentedtoexplainwhattheblackcausingparticleswereintheblackbloomwater．Inthisresearch，thealgae-inducedblackbloomwassimulatedandthechemicalcompositionsofblacksuspendedparticleswhichwereinterceptedunderanaerobicconditionafterthealgae-inducedblackbloomsimulationexperimentwereanalyzedusingmultiX—raybasedapproaches．ScanningelectrondispersiveX--rayspectroscopyandX—-rayfluorescencespectrometeranalysisshowedthatalgaeresiduesandSUS—pendedsedimentparticleswerethemainsubstancesandC，O，andSiwerethemainelementsoftheseblackparticles．Comparedtothechecksamples，blackbloomsuspendedparticlesperformedhigherFeandScontents．DetailedX-rayphotoelectronspectros—copyanalysisforFeandSprovedthatFeweremainlyintheFe(1I)formwhileSweremainlyinSformandthemajorityofthemCO—existedintheformofFeS．Therefore，inthehypoxicandanoxicblackbloomwatercolumn，abundantFeandXS一couldCO—precipitateintoFeS．TheseblackFeScouldsuspendinthewatercolumnorabsorbonsuspendedparticles，whichcausedtheblackcolorofth